The present invention relates to a transport system for transporting rod-shaped objects in an air flow, and more specifically to a transport system for pneumatically transporting filter rods for use in filter cigarettes, toward an apparatus for manufacturing filter cigarettes.
Conventional transport systems of this type comprises a feeder unit, a receiving unit, a transport pipe, and a blower unit. The feeder unit serves to feed rod-shaped objects or filter rods. The receiving unit includes a hopper which receives and temporarily stores the filter rods. The transport pipe, which connects the feeder unit and the receiving unit, can receive the rods from the feeder unit. The blower unit circulates compressed air from the feeder unit toward the receiving unit, through the transport pipe. Thus, the transport system can transport the filter rods from the feeder unit to the receiving unit, utilizing a flow of compressed air in the transport pipe.
In the prior art transport systems described above, if the hopper of the receiving unit has any room to store additional filter rods, the various units continue to be operated, so that the rods are continuously supplied to the hopper. If the hopper is full up with rods, on the other hand, the operations of the units are stopped, so that the rods temporarily cease being fed into the hopper. Thus, the operation of the transport systems is controlled, so that a fixed number of filter rods are stored in the hopper of the receiving unit.
In the conventional transport systems of this type, however, the filter rods may possibly jam a transport path between the feeder unit and the receiving unit. Therefore, these systems are designed such that if a jam occurs in the middle of the transport path, the operations of the individual units are stopped simultaneously. Even though the operations of the units are suspended at the same time, however, the supply of compressed air cannot immediately cease from flowing in the transport pipe, and will continue flowing for a while, from the feeder unit, on the high-pressure side, toward the receiving unit, on the low-pressure side. As a result, the succeeding filter rods successively impact against the preceding ones, accumulating in that portion of the transport pipe near the receiving unit, on the low-pressure side. Thus, the rods may possibly be damaged. If the pressure of the compressed air flowing in the transport pipe is high, that is, if the filter rods flow through the pipe at high speed, they impact against one another with considerable force. Accordingly, the rods may once more jam the transport pipe. The clearing of such a jam in the transport pipe requires much time, thus lowering the operating efficiency of the transport system.
The pressure of the compressed air in the transport pipe, that is, the speed of feed of the filter rods from the feeder unit to the hopper of the receiving unit, cannot be fully increased to its maximum, without entailing the risk of such a jam occurring in the transport pipe.
To fully increase the speed of feed to the hopper to the maximum, two transport paths may be used for the filter rods to be fed into the hopper. In this case, however, a feeder unit, transport pipe, and receiving unit are required for each transport path, thus doubling the costs and space required for the installation of the transport system.